Portable data collection devices have been developed for a wide variety of applications and are becoming increasingly popular as a cost effective mechanism by which to perform a number of essential business activities. While the specific features of such devices vary dependent upon the application, nearly all are designed for and require hand-held rise. Virtually all such devices include a microprocessor based control unit, and further include or provide for the optional attachment of an electromagnetic, laser or CCD scanner for automatic identification of items on which suitable, corresponding electromagnetic or optical identifiers such as tags or bar-code labels have been placed.
For example, portable devices intended to support inventory data collection and control functions such as automatic product identification and price correlation require hand-holding of at least a control unit having a keypad for manual data input and a display, leaving an operator with at most one hand free for other application processing tasks. A scanner having a laser or CCD scan head may be electrically connected by cable to the control unit (such as the Model LS 2000 Series commercially available from Symbols Technology, Inc. of Bohemia, N.Y.). Alternatively a separate scanner (such as disclosed in U.S. Pat. Nos. 5,021,642; 4,758,717; 4,460,120; 4,387,297; or 4,251,798) may be physically incorporated within the control unit. Typical of the latter is the Model LRT-3800 manufactured by Symbol Technologies, Inc. of Bohemia, N.Y.; the Model PTC-960 provided by Telxon Corporation of Akron, Ohio; and the Model PSC 5300 from Photographic Sciences Corporation of Webster, N.Y. which is available with an optional integral display.
Whether devices such as these are operable or convenient for use in particular applications requires consideration of the features each posses, how each is carried by the operator, and its size, weight and visual usage. For example, where one or both of an operator's hands must be used to support the device and any attachments, the device may not be operable as a portable POS terminal because the operator may be unable to hold or position for scanning a product for sale. Also, the larger or heavier the device, the less desirable or practicable for applications requiring long periods of hand-held support by an operator. Indeed when certain features (like wireless transceivers and printers) that are necessary for various applications are included, the devices become so large and heavy that even hand-grip pedestals furnished to facilitate scan positioning are inadequate for long-term operator support.
Among the least appreciated, but possibly most significant usage consideration for applications requiring, and devices including a scanner, is the visual relationship between the display, scanning beam and operator's line of sight. In those instances, correct alignment of the beam to the tag or label target is imperative for successful operation. For this to be effectively accomplished, the positions of the scanning beam and the target must be known to and simultaneously within the operator's line-of-sight. Many applications also necessitate contemporaneous reading of the display by the operator in order to receive certain processing information, as when the operator wishes to confirm entry of a correct product code by a bar code scanner or confirm related information such as shelf pricing.
Presently the only devices allowing simultaneous line-of-sight viewing of the scanning beam and display during use are those devices where the scanner is integrally incorporated into the control unit with the display, such as Symbol Technologies' Model LRT-3800, Telxon's Model PTC-960, Photographic Sciences' Model PSC 5300, and the Model BHT-2000 Bar-code Handy Terminal more recently made commercially available in the United States by the Nippondenso ID Systems division of Toyota Tsusho America Inc. of San Mateo, Cal. Unfortunately the weight and size of these devices often makes optimal beam positioning difficult or impracticable and renders them effectively inoperable for various applications as portable POS where the operator's hands are required for other activities during operation.
U.S. Pat. Nos. 4,923,818 and 4,621,189 disclose portable data entry devices with scanner heads that are detachable from the control unit upon which they are mounted during operation to allow a reversal of the direction of beam projection. However, these devices will not operate while the scanning head is detached and otherwise suffer from all the same deficiencies as the devices noted hereinbefore.
Thus, despite the increased popularity and desirability of portable data entry devices to perform an ever increasing range of tasks, no device has been provided that is readily capable of use in more than a limited number of applications, particularly with any significant extent of operator flexibility.